It's possible that Apple could make the Watch smaller and smaller every few years as technology advances.But remember: Rolex, Omega, and TAG Heuer, for example, never slim down their flagship watch models.Doing so would obsolete the Rolex you bought in 2012, and that obsolescence would hurt sales.If Apple wants to break into the high-end watch market for the long run, they'll keep the Watch design as-is. I think it's quite possible that the Watch will remain the same...

Doubtful: Apple iCar.
Tim Cook: "Oh, and there's one more thing. You're sick and tired of being stuck in traffic on your commute. Am I right here people? YEAHHH!! YOU KNOW IT!!! Well, we at Apple are sick and tired of the whole automotive experience as we currently know it. The sleazy dealers, the high depreciation, the high cost of maintenance, the depletion and pollution of our natural resources, and the time wasted on the road. That's time out of your lives...

My point exactly. Gen 1 Watch case stays the same forever, electronics are upgraded over time for a fee.Apple might release new models alongside the first one over time. E.g. MacBook Pro, MacBook Air. It could be something like this: upgrade the battery for $99, upgrade battery + electronics for $199 (or more).On the other hand, maybe Apple will require upgrading the electronics along with the battery.No decision for techno-moron end-users to make, and it would keep...

Rolex hasn't changed the thickness of their Submariner or Oyster Datejust or Day-Date. Ever.They don't feel the need to compete against, say, Patek Philippe in "thin." So why should Apple make their first Watch series thinner over time?Better to release all-new thin models later in addition to the thick ones.Think Watch Air.